Process for facing sheets or objects of aluminum and the like with sheets of heavy metal



lllll Patented Apr. 28, 1925.

v.AUGrUSTO PASSALACQUA, PARIS, FRANCE;

PROCESS FOR FACING SHEETS OR OBJECTS OF ALUMINUM AND THE LIKE WITH SHEETS 0F HEAVY METAL.

No Drawing. Application filed December 21, 1923. SerialNo. 682,114. To all whom it may concern: ing from the spirit and scope of the inven Be it known that I, AUeUsTo PAssALAotion.

QUA,.Sl 1lZ )j80t of the King of Italy, residing Formula A. at Par-1s, France, post-office. address 17 Rue Ste du General Brunet, have invented certain P TA; am 18 new and useful Improvements in Processes i n 18 for Facilng Sheets or Objects of Aluminum i i-g 7""" 18 and the ike With Sheets of Heavy Metal of whipah the following is a specification. 3 011 or generally any othei 18 T e present invention relates to a process which enables sheets or objects of aluminum s i g; analogous fatty Sub 10 or Its alloys to be faced or lined with sheets f of heavy metal, such as copper, adapted to 100 form a protective layer. The sheets of the protective metal may be exceedingly thin in order to prevent the final product from becoming too heavy whilst at the same time efi'ectively protecting the aluminum.

The advantages of aluminum with a. fac- The linseed oil and the olive oil can be re placed by any other analogousoils.

Fownula c. c. Urdinary or distilled Water. 1, 000

ing of copper s'houldbe obvious without be- Stannous chloride mg emphasized, in view of the large number Aluminum sulphaIhg 1 67 of ubses to which aluminum thus protected Aluminum 82 can e put. The sheets of copper or other heavy metal ggfiy ggfigg are preferably exceedingly thin, for example 10% aqueous l gg some hundredths of a millimetre. soda The covering is efiected in the following Stannous QGEBQ JTI'TI manner: i y The surfaces are first carefully cleaned. g gg ig g 5" The aluminum or the like to be cleaned is Potassium g g7 80 first slightly heated to about 100 (1., and Potassium ferroc g ifig 80 then a pickling composition prepared in the y nlllanner hereinafter descrilpled is 1spread Formula; 0. t ere'u on. The heatin oft emeta is con tinned? It first become entirely black, and gig gi gg ilfibga thereupon becomes White as in its normal Ci'tric acid 80 state. c

The cleaningcomposition is produced by Dlstlned Water 000 mixing together four compositions A B 7 Formula D. CD, said mixture being effected under cer- Stannous chloride 80 tain conditions which will hereinafter be Sodium QEEII: 90

described.

. Each of the. compositions A B-CD is composed of a certain number of substances which are specified below.

The proportions of the substances hereinafter specified are merely given by way of example and may actually vary within wide limits without interfering with the cleaning properties of the composition. The proportions may thus be modified without depart- Distilled Water 1, 000

The method of obtaining the cleaning paste used for the tinning will now be described.

First a mixture is made of equal parts or of any other proportions of solutions BC and D.

Thereupon this mixture is added to the composition A in any suitable proportions,-

, num lined with copper.

and the resultant mixture is brought to boil mg.

The copper or other heavy metal such as for example lead, may be cleaned in the same way as the aluminum. In order to clean the heavy metals, the ordinary pickling compositions, such as hydrochloric acid, ammonium chloride and the like may also be used.

The cleaning of the aluminum or its alloys as Well as that of the copper or of the other heavy metals may be effected by means of a metallic brush or by any other suitable means.

As soon as the two pieces, of aluminum on the one hand, and of copper on the other hand, have been thoroughly cleaned, their heating is continued until they reach a temperature which lies between about 300 and 550 0., whereupon tin is applied to the surface of the aluminum which: is to be faced with the sheet of copper. The copper sheet is thereupon applied to the surface of the aluminum sheet which is coated with tin, and the two pieces thus juxtaposed are subjected to a pressing operation in a hydraulic press or any other suitable press. The pressure is maintained until the metal is almost completely cool.

On leaving the press the two pieces are united. The tin, used for uniting the aluminum and the copper or other metal or alloys may be employed in the pure state or mixed with other metals melting at a low temperature. The tin may also be entirely replaced by one of these metals or by alloys of these metals. Amongst such metals which are adapted to be added to or substituted for tin, zine may be mentioned in the first place.

The above-described cleaning is an operation which becomes more essential with increasing purity of the aluminum used. If the aluminum used is mixed with zinc, this operation becomes less necessary as the proportion of zinc increases. The considerations specified with regard to zinc are obviously also applicable to other impurities in the aluminum.

It should be well. understood that the process is applicable both to pure metals as well as to their alloys.

Thus the sheet of light metal, instead of consisting of pure aluminum, can consist of alloys of aluminum with lead, tin or the like, or of duralumin and the like.

Moreover, the sheet of protective metal may consist of copper or of other heavy metal alone or alloyed with other metals.

The hereinbefore described process en ables all receptacles of co per or of other heavy metals used in aviation: to be replaced by'very light receptacles of alumi- Thus their weight is very considerably lightened, the importance of which increases with the dimensions of the receptacles.

When employing alloys of aluminum which are very resistant, such as for example duralumin, it will be found that an increase in resistance is obtained when comparing a receptacle obtained in accordance with the present process with a receptacle of the same weight consisting entirely of copper. Receptacles produced in accordance with the new process are also more economical than receptacles consisting entirely of copper.

The above considerations applied by way of example to receptacles are also applieable to any other objects manufactured according to the present. process.

Whilst the process has hereinbefore been described in connection with the facing of aluminum and its alloys, the same may also be applied to the facing of sheets of other metal.

I claim:

1. The process for lining objects of light metal with a heavy metal adapted to form a protective layer, which comprises heating the light metal object and the covering sheet of heavy metal, carefully cleaning the surfaces of said pieces to be joined together, continuing heating of the light metal, un

til it attains a temperature of between 300 C. and 550 C., spreading a metal of a low melting point over the surface of said light metal, superimposing the heated heavy metal sheet upon said spread surface and pressing the two juxtaposed pieces strongly together.

2. The process for lining objects of light metal with a heavy metal adapted to form a protective layer, which comprises heating the light metal object and the covering sheet of heavy metal, carefully cleaning the surfaces of said pieces to be joined together, continuing heating of the light metal, spreading a metal of a low melting point over the surface of said light metal, superimposing the heated heavy metal sheet upon said spread surface, pressing the two juxtaposed pieces strongly together and maintaining the pressure until practically complete cooling of the metallic object.

3. The process for lining objects of aluminum and its alloys with an exceedingly thin coating of heavy metal adapted to form a protective layer, which comprises heating the aluminum object and the covering sheet of heavy metal, carefully cleaning the surfaces of said pieces to be joinedtogether, containing heating of the aluminum-containing piece, spreading a metal of a low melting point over the surface of said aluminum-containing piece, superimposing the heated heavy metal sheet upon said spread surface and pressing the two juxtaposed pieces strongly together.

ed to form a protective layer,

4. The process for lining objects of aluminum and its alloys with an exceedingly thin coating of heavy metal adapted to form a protective layer, which comprises heating the aluminum-containing object and the covering sheet of heavy metal, carefully cleaning the surfaces of said pieces to be joined together, continuing heating of the aluminum-containing piece, spreading a metal of a 10W melting point over the surface of said aluminum-containing piece, superimposing the heated heavy metal sheet upon said spread surface, pressing the two juxtaposed pieces strongly together and maintaining the pressure until practically complete cooling of the metallic object.

5. The process for lining objects of aluminum and its alloys with an exceedingly thin coating of copper and its alloys adapt- I which comprises heating the aluminum-containing object and the covering sheet of copper-containing metal, carefully cleaning the sun faces of said pieces to be joined together, continuing heating of the aluminum-containing piece, spreading a metal of a low melting point over the surface of said aluminum-containing piece, superimposing the heated copper-containing metal sheet upon said spread surface, pressing the two juxtaposed pieces strongly together and maintaining the pressure until practically complete cooling of the coated object.

6. The process for lining objects of aluminum and its alloys with an exceedingly thin coating of copper and its alloys adapted to form a protective layer, which comprises heating the aluminum-co'ntaining object and the covering sheet of copper-com taining metal, carefully cleaning the surfaces of said pieces to be joined together,

continuing heating of the aluminum-containing piece, spreading tin-containing metal over the surface of said aluminum-containing following ingredients piece, superimposing the heated copper-containing metal sheet upon. said spread surface, pressing the two juxtaposed pieces strongly together and maintaining the pressure until practically complete cooling of the coated object; I

LA pickling composition, comprising a paste composed of stearic acid, paraffin, resin, linseed oil, olive oil and lard; and a mixture of three aqueous solutions added to said paste and composed of: (1) stannous chloride, aluminum sulphate, aluminum chloride, sodium pyrophosphate, salammoniac, caustic soda, stannous sulphate, nitric acid, zinc chloride, potassium cyanide, and potassium ferrocyanide; (2) nickel sulphate, ammonium chloride, and citric acid; and (3) stannous chloride and sodium pyrophosphate.

8. A pickling composition, comprising the in substantially the following proportions by Weight, viz: a paste composed of 18 parts paraflin, 18 parts resin, 18 parts 1in seed oil, 18 parts olive oil, and 10 parts lard; and a mixture of three solutions composed of: (1) 60 parts stannous chloride, 67 parts aluminum sulphate, 82 parts aluminum chloride, 60 parts sodium pyrophosphate, 85 parts salammoniac, 90 parts of a 10% aqueous solution of caustic soda, parts stannous sulphate, 70 parts nitric acid, 55 parts zinc chloride, 80 parts potassium cyanide, 80 parts potassium ferrocyanide, and 1000 parts water; (2) 75 parts nickel sulphate, 90 parts ammonium chloride, 80 parts citric acid, and 1000 parts water; and (3) 80 parts stannous chloride, 90 parts sodium pyrophosphate, and 1000 parts water.

In testimony whereof I ,aflix my signature.

AUGUSTO PASSALACQUA.

parts stearic acid, 18 

